Abstract: The effect of sodium chloride concentration, p H, enzyme acting temperature, time and its adding amount on the gel hardness and water holding capacity of egg white treated by transglutaminase were studied in this experiment.The SDS- PAGE electrophoresis was used to analyze the protein crosslinking after enzyme treatment to explore the mechanism of transglutaminase on heat coagulation of egg white. The results showed that the gel hardness and water holding capacity of egg white was increased significnatly after TGase treatment ( p < 0.01) .When sodium chloride concentration was 0.4mol / L, p H was 6.0, temperature was 35℃, acting time was 3.5h and the TGase addition was 10 U / g protein, the value of gel hardness and water holding capacity of egg white reached their maximum value of ( 134.73 ± 1.79) g and 93.83% ± 0.58%, which were 58.87% and 29.38% higher than that of control group, respectively. The SDS- PAGE electrophoresis analysis showed: TGase could contribute to the crosslinking of protein molecules in egg white under certain conditions, which improved the heat coagulation of egg white.